Not anymore, pet spells require a key to be hit. I believe Servitude you can bind a "do the smart thing" key. Where if you press it Servitude will try and figure out what's the best ability to use at that moment. However, I don't use Servitude anymore so don't quote me on this.

No you cannot do this. Conditional commands (like sacrificing a voidwalker when below 25%) cannot be used in combat (for the most part). Also I don't think you can hook things into movement keys and such anymore.